Peroxy compounds containing a carbonate group

ABSTRACT

A new class of compounds: R-W-R&#39;&#39; where R and R&#39;&#39; are identical oxy radicals containing peroxide functions such as dialkyl or diaralkyl peroxide, peroxyketal, peroxyester, or monoperoxycarbonate, and W is a carbonyl group, or carbonyl containing group, or an alkylidene or aralkylidene group, or a phosphorus containing group. Examples: Di(1,3-dimethyl-3-(t-butylperoxy)butyl) carbonate; Di(1,3-dimethyl-3-(n-butoxycarbonylperoxy)butyl) carbonate; 2,2-Bis(3,3-di(t-butylperoxy)butoxy)propane; Di(1,3-dimethyl-3-(t-butylperoxy)butyl) ethyl phosphate. They are free radical affording compounds useful in crosslinking of polyolefins and unsaturated polymers, and for the polymerization of vinyl monomers and diolefinic monomers.

United States Patent [191 DAngelo et al.

[ Apr. 3, 1973 [S4] PEROXY COMPOUNDS CONTAINING A CARBONATE GROUP [75]Inventors: Antonio Joseph DAngelo, Buffalo; Orville Leonard Mageli;Chester Stephen Sheppard, both of Kenmore, all of NY.

[73] Assignee: Pennwalt Corporation,Philadelphia,

[22] Filed: June 17, 1968 [211 App]. No.: 737,359

[51] Int. Cl ..C07c 73/00, C08f 1/60 [58] Field of Search ..260/463 [56]References Cited UNITED STATES PATENTS 3,236,872 2/1966 Manly et al..260/453 2,370,566 2/1945 Muskat et al ..260/78 2,385,932 10/1945Muskat et a1 ..260/78 3,275,661 9/1966 Widmer et al ..260/348 OTHERPUBLICATIONS Malone et al., J. Am. Chem. Soc. vol. 51, pp.

3424-3427, November 1929.

Barusch et al., J. Am. Chem. Soc. Vol. 75, pp. 1987-1988, April, 1953.

Chemical Abstracts, Vol. 65, 2173(a) (1966).

Primary Examiner-Lewis Gotts Assistant ExaminerDiana G. RiversAttorney-William D. Mitchell [57] ABSTRACT A new class of compounds:R-W-R where R and R are identical oxy radicals containing peroxidefunctions such as dialkyl or diaralkyl peroxide, peroxyketal,peroxyester, or monoperoxycarbonate, and W is a carbonyl group, orcarbonyl containing group, or an alkylidene or aralkylidene group, or aphosphorus containing group.

Examples:

Di[ 1 ,B-dimethyl-S-(t-butylperoxy)butyl] carbonate; Di[l,3-dimethyl-3-(n-butoxycarbonylperoxy)butyl1 carbonate; 2,2-Bis[3,3-di(t-butylperoxy)butoxyIpropane; Di[ 1 ,3-dimethyl-3-(t-butylperoxy)butyl] phosphate.

ethyl They are free radical affording compounds useful in crosslinkingof polyolefins and unsaturated polymers, and for the polymerization ofvinyl monomers and diolefinic monomers.

12 Claims, No Drawings PEROXY COMPOUNDS CONTAINING A CARBONATE GROUPBACKGROUND OF THE INVENTION 1 The Field of the Invention This inventionrelates to peroxides obtainable by the coupling of hydroxide groupcontaining peroxides. Particularly the invention relates to coupledperoxide containing one or more carbonyl groups or an alkylidene groupin the portion of the molecule which forms the linkage between the twoperoxy containing portions of the coupled peroxide molecule. Also theinvention relates to methods for preparing such coupled peroxides.

2. Description of the Prior Art No prior art is known with respect tothe coupled peroxides of the invention.

U. S. Pat. No. 3,236,872 discloses dialkyl peroxides containing hydroxylgroups, e.g., 2-methyl-2-(t-butylperoxy )-4-pentanol.

A copending application, Ser. No. 569,030 (now US. Pat. No. 3,542,856),filed Aug. 1, 1966 discloses peroxyesters containing hydroxyl groups,e.g., t-butylperoxy-3-hydroxypropionate.

Still other precursors, hydroxy substituted pero yketals are disclosedin a copending application, Ser. No. 727,336 filed May 7, 1968, e.g.,3,3-Bis(t-butylperoxy)-l-butanol.

SUMMARY OF THEINVENTION It has been discovered that high puritypolyfunctional peroxides, i.e., at least two peroxy groups, can beprepared by a coupling reaction carried out on a hydroxy groupcontaining peroxide.

The novel polyfunctional peroxides of this invention have the generalformula:

where:

1. R and R are identical, and each contain at least one peroxy (-00-)group selected from the class where R and R each fall into the samemember (i)-(vi) respectively and the R R 1%, R R R and R required to bepresent in the particular R is the same as the corresponding radical[i.e., R R R R R R and R as the case may be required to be present inthe corresponding R. To illustrate: If R is:

R R and R are identical in both R and R.

2. W is a diradical selected from the class consisting of: I i

m) n i (iii) 0 r i-R ip l R5 and 3. R and R are aliphatic having l-l 2carbon atoms,

cycloaliphatic having 3-12 carbon atoms, or aromatic having 6-12 carbonatoms;

4. R is aliphatic or cycloaliphatic, each having 4-10 carbon atoms andthe carbon atom joined to the peroxy oxygen atom is a tertiary carbonatom;

5. R is aliphatic having l-lO carbon atoms or cycloaliphatic having 3-12carbon atoms;

6. R is lower alkyl, cycloalkyl, aralkyl aryl, alkoxy,

cycloalkoxy, aralkoxy, or aryloxy;

7. R is H or lower alkyl;

8. Y is the diradical o, s, or N41,;

9. R is an aliphatic diradical having 1-10 carbon atoms or acycloaliphatic diradical having 3-12 carbon atoms;

10. R is an aliphatic diradical having l-lO carbon atoms, cycloaliphaticdiradical having 3-12 carbon atoms, or aromatic diradical having 612carbon atoms;

1 1. R and R are selected from the class consisting of H, alkyl of 1 10carbons and cycloalkyl of 3-12 carbons and when R is H, R,, can also bearyl of 6-12 carbons and R and R can together form an alkylene biradicalof 2-1 1 carbons; and

12. R is a diradical selected from the class consisting i. R ii. YR Y(iii) 0 o miiyluyr zm (iv) 0 0 YRBY(H1YR3Y(HJYR3Y Illustrative peroxidesare:

Di[ I,3-dimethyl-3-(t-butylperoxy)butyl] carbonate.

Di[4,4-di(t-butylperoxy)pentyl] carbonate.

Di[ 1 ,3-dimethyl-3-(t-butylperoxy )butyl] succinate.

Ethylene Bis[ l,3-dirnethyl-3-(t-butylperoxy)-butyl carbonate].

Di[ 1 ,3-dimethyl-3-(t-butylperoxy )butyl] phosphate.

2 ,2-Bis[ 3 ,3-di(t-butylperoxy)butoxy] propane.

N,N'-m-phenylene bis[O-[ 1,3dimethyl-3-(t-butylperoxy )butyl]carbonate].

DESCRIPTION OF THE INVENTION AND EXAMPLES The aliphatic radical includessubstitution by aryl radicals araliphatic radicals and cycloaliphaticradicals. The cycloaliphatic radical includes substitution by aliphaticand by aryl radicals. The aromatic and aryl radicals may be substitutedby aliphatic and by cycloaliphatic radicals. Both cycloaliphatic,aromatic and aryl radicals may be single ring, such as phenyl andcyclohexyl, or connected rings, such as biphenyl, binaphthyl,bicyclopropyl, bicyclopentyl, or fused rings such as naphthyl,decahydronapthyl. It is to be understood that the substituents shouldnot interfere with the desired coupling reaction. In general halogen,ester, ether, thioether, and carbonate substituents or groups containingthese do not interfere. Desirably R R R R R R and R contain only carbonand hydrogen atoms.

Commonly R is alkyl or alkoxy having 1-6 carbon atoms; cycloalkyl orcycloalkoxy having a total of 3-12 carbon atoms; aralkyl or aralkoxyhaving 7-12 carbon atoms; aryl or aryloxy having 6-12 carbon atoms.

Commonly, R is H or alkyl having 1-4 carbon atoms.

Commonly R and R are each H or alkyl having 1-4 carbon atoms or one canbe aryl while the other is H or R and R together can form an alkylenebiradical.

R is an aliphatic or cycloaliphatic radical, each having 4-10 carbonatoms, affording a t-carbon atom which is joined to a peroxy oxygenatom. For example.

The described coupled peroxy compounds are effective crosslinking agentsfor polymeric materials which are capable of being crosslinked to form atherrnoset material.

ethyl Illustrative classes of polymeric materials where these new peroxycompounds are effective include: homopolyrners, such as poly(vinylchloride) and polyolefins (e.g. polyethylene and polybutenes);elastomers, such as natural rubber and synthetic rubber (e.g. butylrubber, GR-S rubbers, neoprene, acrylic rubber, Buna rubber,ethylene-propylene rubber, silicone rubbers, and miscellaneouselastomeric material such as polybutene-styrene copolymers and urethanerubber), copolymers such as poly-(ethylene-vinyl acetate) andcondensation polymers such as polyamides, polyesters (both saturated andunsaturated) and polycarbonates. The polymer may contain a plasticizerand/or oil extenders and/or fillers such as carbon black, silica andcalcium carbonate. Also they are effective in curing (crosslinking)mixtures of vinyl monomers and unsaturated polyesters.

Also they are effective for the polymerization, to form solid polymers,of unsaturated monomers capable of polymerization by a free radicalmechanism. For example, vinyl monomers such as vinyl halides; vinylidenehalides; vinyl esters such as vinyl acetate and vinyl stearate; thevinyl toluene; the acrylics such as acrylic acid, methyl methacrylateand ethyl acrylate. Other monomers are: The styrene-butadiene blends forrubber copolymers; styrene-acrylonitrile blends for copolymers;fluoroethylenes and chlorofluoroethylenes; butadiene; isoprene andsimilar polymerizable dienes.

UTILITY AND DISCUSSION These novel coupled peroxycompounds can beutilized in the following ways:

1. They can crosslink polyethylene, polyethylenepolypropylene rubber,polyolefin elastomers, urethane rubbers, silicon rubber etc. (ExampleXIII, Tables I, II, III and IV) 2. They can polymerize monomerscontaining polymerizable ethylenic grouping. (Example XIV) 3. They cancure resins curable by free radical producing agents. (Example XV) 4.They can be used as free radical sources and/or catalysts in organicsyntheses and applications where free radicals are required.

Some of the desirable properties that a peroxide has to have to beuseful for crosslinking polyethylene are: low volatility, high thermalstability, and good efficiency with respect to its active oxygencontent.

The volatility and the thermal stability are necessary requisites, sincethe peroxide has to tolerate the high temperatures of the millingoperation, which is a necessary step to incorporate the peroxide withthe polymer before the crosslinking process. If the peroxide is toovolatile (as in the case of di-t-butyl peroxide) there would not be anyperoxide left for the crosslinking process at the end of the millingstep. If the peroxide is not volatile, but its thermal stability is low,a premature decomposition of the peroxide will take place during themilling step, which results in a premature crosslinking of the polymer.If this happens, the polymer cannot be shaped or formed any furthersince the thermoplastic polymer has become thermoset too soon.

Efficiency is another property that a good crosslinking peroxide has tohave in order to make the crosslinking process economical and efiective.

Another advantage of the difunctional peroxides obtained by the couplingreaction is that they utilize their active oxygen content to the fullextent. Some of the known commercial difunctional peroxides like 2,5-dimethyl-Z,5-di(t-butylperoxy)hexane and 2,5-dimethyl'2,5-di(t-butylperoxy )-hexyne-3 are not as efficient inutilizing their active oxygen content as the difunctional peroxide ofour invention (see Table I). This is an unexpected result.

We have demonstrated that hydroxy containing peroxides, such as2-methyl-2.-(t-butylperoxy)-4-pentanol, do not have all the desirableproperties of a good crosslinking agent. Its volatility is low and itsthermal stability is good, but its efficiency is poor. (see Table I) Bycoupling this hydroxy containing peroxide, using the process describedin Examples I, H, and III, we

found the coupled product to be an exceptionally good crosslinking agentpossessing all the desirable properties. (see Table I) [The half-life ofthe coupled products (e.g. from Examples I, II, III, and V) is almostdouble that of the hydroxy containing peroxide precursors. This, to saythe least, is unexpected] (see Example XVI) [Another advantage of thecoupling reaction is the simplicity of preparing pure difunctionalperoxides without going through tedious purification steps that arenecessary when they are prepared peroxidizing difunctionalintermediates] The coupling reaction is not the only expedient one canuse to improve volatility of the hydroxy containing peroxides. One canacylate the hydroxyl group with a sufficiently high molecular weightacylating agent and the volatility will be reduced. Using too low of amolecular weight acylating agent will not lower volatility sufficientlyunless the starting hydroxy-containing peroxide is already ofsubstantial molecular weight.

The disadvantage of this approach is that an increase in the molecularweight of the peroxide is attained at a sacrifice of active oxygencontent.

Peroxides are sold by the pound and used according to the active oxygencontent. So, if one had to buy a high molecular weight product withsmall active oxygen content, larger amounts of the product would have tobe used to obtain the desired results in that particular application.

The coupled compounds of our invention minimize this disadvantage, sincethey gave the desirable properphosgene, diacid chlorides,bischloroformates, diiso-- ties without excessively increasing themolecular 5 weight.

Thus, the coupling reactions of hydroxy-containing peroxides R-H, affordnovel peroxides, R-W-R', that are unexpectedly more stable than R-H:more efficient than R-H and other commercial diperoxides; and at thesame time are less volatile than R-l-I and simple derivatives of R-H.

PREPARATION One mole of the hydroxy-containing peroxide is first reactedwith one mole of hydroxy coupling agent to attain an intermediateproduct.

The preparation of certain of these intermediate products is disclosedin copending application Ser. No. 727,323 filed May 7, 1968, now U.S.Pat. No. 3,671,651.

This intermediate product can subsequently be reacted with another moleof the hydroxy-containing peroxide in a second step to form R-W-R'.Illustrative reactions are: (21).. O

-HCl g RH 00012 R 0; followed by (d) 0 Ii 0 o H JlttllHOCl llS ms "21161nomosmsolwm When the intermediate product is a chloroformatecontainingperoxide, it can also be convened directly to R-W-R' in the second step,e.g.

(I!) O ll tcrt-amine 2x001 RCR co. +1101 The reaction conditions dependupon the characteristics of the reactants and peroxy products. Ingeneral the intermixing of the coupling agent and the peroxy compound iscarried out from about C. to +25 C., and then the reaction temperaturemay be increased to a maximum of not more than 100 C., to allow thereaction to go to completion. Preferably the maximum reactiontemperature should be not more than about 60 C.

The reactions may take place in the presence or absence of an inertdiluent or solvent. In certain cases, where one or more of the reactantsare solids, such a diluent is necessary to provide intimate contact ofthe reactants; in other cases the diluent provides an additional safetyfactor, as some pure products are hazardous.

In certain cases the presence of a base may be necessary i.e. Method I(i), (ii), (iii), and (iv) or Method II and (f)- Any compound, inorganicor organic in nature, which functions as an acid acceptor (base) for theacid by-product of the reaction can be used.

Illustrative of organic bases are: pyridine, and substituted pyridines;lower alkyl tertiary amines such as tn'methyl amine, and triethylamine;dirnethyl aniline; and N-methyl-Z-pyrrolidone.

Illustrative inorganic bases which can be used are the basic salts ofalkali metals and alkaline earth metals such as sodium, and potassiumcarbonates, and sodium and potassium hydroxide.

The above methods of preparation of the novel peroxides, R-W-R, arefurther illustrated in Examples I to XII.

EXAMPLE I Preparation of Di[l,3-dimethyl-3-(t-butylperoxy)butyl]carbonate ond To a mixture of 22.6 g. (0.1 mole) of2-methyl-2-(tbutylperoxy)-4-pentanol (84 percent) and 15.8 g. (0.2 mole)of pyridine in 50 ml. OF hexane cooled to 51.- 1 C. was added a solutionof 5 g. (0.05 mole) of phosgene in 50 ml. of hexane.

mixture was allowed to react for 48 hours at this temperature.

The reaction mixture was filtered from the pyridine hydrochloride andthe organic phase washed with 10 percent tartaric acid solution andwater to neutrality.

The organic phase was then dried over anhydrous magnesium sulfate,filtered and the solvent evaporated under reduced pressure. A slightlycolored liquid was obtained, 20.1 g., theoretical 20.3 g. The infraredspectrum (I.R.) of this material showed presence of trace amounts ofunreacted 2-methyl-2-(t-butylperoxy)-4- pentanol.

The unreacted material was distilled under reduced pressure at 34-35 C.and 0.05 mm. of Hg. The LR. of the residue was free of OH and containedthe characteristic bands of the desired product.

EXAMPLE II PREPARATION OF [A] To a solution of 27.2 g. (0.1 mole) of1,3-dimethyl-3- (t-butylperoxy)butyl chloroformate (93.5 percent)(prepared from 2-methyl-2-(t-butylperoxy)-4-pentanol and phosgene) in 75m1. of diethyl ether, cooled at 15: 1 C. was added a solution of 7.9 g.(0.1 mole) of pyridine in 25 m1. diethyl ether. The pyridinechloroformate complex separated at first and then dissolved, giving apink colored solution. While the reaction temperature was controlled15i- 1 C., a solution of 22.6 6. (0.1 mole) of 2methyl-2-(t-butylperoxy)-4- pentanol (84 percent) in 50 ml. of diethylether was added dropwise.

After the addition was completed, the mixture was allowed to reflux for24 hours at 36: 1 C. At the end of this period the reaction mixture wasfiltered from the pyridine hydrochloride and washed with 10 percentsolution of tartaric acid and water to neutrality. The ether solutionwas dried over anhydrous MgSO filtered and the solvent evaporated underreduced pressure and then under vacuum at 0.1 mm. of Hg and a bathtemperature of 60 to C. A liquid was obtained (40 g.); theoretical yield40.6 g.

The IR. of this liquid was free of OH and C-Cl bands and contained thecharacteristic bands of the desired prduct.

EXAMPLE III PREPARATION OF [A] To a solution of 29.2 g. (0.1 mole) of1,3-dimethyl-3- (t-butylperoxy)butyl chloroformate (86.5 percent) indiethyl ether at 23: 1 C. was added a solution of 7.9 g. (0.1 mole) ofpyridine in 10 ml. of diethyl ether. To this mixture was added dropwise0.6 g. of H 0 at such a rate that the evolution of CO could becontrolled to a reasonable rate. The reaction temperature rose to about30 C. The reaction mixture was allowed to react at room temperature (23C.) until the CO evolution ceased (24 hours). The reaction mixture wasdiluted with H 0 and the organic phase was separated, washed with 10percent solution of tartaric acid and H to neutrality.

The other solution was dried over anhydrous MgSO filtered and thesolvent evaporated under reduced pressure and then under vacuum at 0.1mm. of Hg. and a bath temperature of 6070 C. A liquid was obtained 16.2g.; theoretical yield 20.3 g.

The IR. of this material was free of OH and C-Cl bands and contained thecharacteristic bands of the desired product.

EXAMPLE IV Preparation of Di[4,4-di(t-butylperoxy)pentyl] carbonateC(-CHa)a H M O O o H 0 CH3--CHr-CHg-CH:-O-C' OCHZCH -CHQ( JCH3 (I) 0 0C(-C a)a C( a)a To a mixture of 3.0 g. (0.0295 mole) of4,4-di'(t-butylperoxy)--pentanol (97.3 percent), 2,4 g. (0.0295

mole) of pyridine in '50 ml. diethyl ether cooled at 5: 1 C. was added asolution of 1.45 g. (0.0147 mole) of phosgene in 25 ml. of diethylether. After the addition was completed, the reaction mixture wasallowed to stir for 6 hours at 23: 1 C. After this time, the pyridinehydrochloride was filtered off and the ether solution was washed withpercent solution of tartaric acid and water to neutrality. The etherphase was dried over anhydrous MgSO filtered and the solvent evaporatedunder reduced pressure. A liquid was obtained, 8.5 g.

The l.R. indicated that the desired product was obtained.

EXAMPLE V Preparation of Di[2-(t-butylperoxycarbonyl)ethyl] carbonate Toa mixture of 17.4 g. (0.1 mole) of t-butyl 3- hydroxyperoxypropionate(93 percent) and 7.9 g. (0.1 mole) of pyridine in diethyl ether cooledat 5: 1 C. was added a solution of 30.5 g. (0.1 mole) of 2-(t-buty1-peroxycarbonyl)-ethyl chloroformate (75 percent) in 50 ml. of diethylether.

After the addition was completed the reaction mixture was allowed tostir for 1 hour at 30: 1 C. At the end of this period the reactionmixture was filtered off from the pyridine hydrochloride and the ethersolution was washed with 10 percent solution tartaric acid and water toneutrality. The ether solution was dried over anhydrous MgSO filteredand the solvent evaporated under reduced pressure. A colorless liquidwas obtained (41 g.). The IR. of this material showed the characteristicbands for the desired product.

EXAMPLEVI Preparation of Di[l,3-dimethyl-3-(n-butoxycarbonylperoxy)-butyl carbonate C II; (I) II; (II) $113 0 H3 (11:0 =0 0 O 04H: C4Hn Toa mixture of 26.0 g. (0.1 mole) of 0,0-(l,1- dimethyl-3-hydroxybutyl)O-butyl monoperoxycarbonate percent) and 7.9 g. (0.1 mole) of pyridinein 50 m1. of diethyl ether, cooled at 10: 1 C. was added a solution of31.4 g. (0.1 mole) of 1,3-dimethyl- 3-(n-butoxycarbonyl-peroxy)butylchloroformate in 50 ml. of diethyl ether, at such a rate that thereaction could be controlled at 10:: 1 C.

After the addition was completed, the reaction temperature was allowedto rise to 2325C. and allowed to stir for 1 hour. At the end of thistime, the reaction mixture was diluted with water and the organic phaseseparated and washed with 10 percent solution of tartaric acid and watertoneutrality. The ether phase was dried over anhydrous magnesiumsulfate, filtered and the solvent evaporated under reduced pressure andthen under vacuum at 30 to 35 C. and 0.05 mm. of Hg. A liquid wasobtained, 45.3 g.

The LR. of this material indicated that the desired product wasprepared.

EXAMPLE VII Preparation of Di[l,3-dimethyl-3 (t-butylperoxy)butyl]succinate I A mixture of 4113 g. 0.02 mole) of2-methyl-2-(tbutylperoxy)-4-pentanol (92 percent) and 1.5 g. (0.01 mole)of succinyl chloride and 25 ml. of diethyl ether was refluxed for 48hours.

Evolution of hydrochloric acid could be detected as the mixture wasrefluxing. At the end of 48 hours no more HCl could be detected.

The mixture was stripped under reduced pressure. A slightly yellowcolored liquid was obtained weighing 4.4 g.; theoretical yield 4.42 g.

The IR. of this material was free of OH and C-Cl bands and contained thecharacteristic bands of the desired product.

EXAMPLE VIII Preparation of EthyleneBis[1,3-dimethyl-3-(t-butylperoxy)-butyl carbonate] To a mixture of 29.4g. (0.1 mole) of 1,3-dimethyl-3- (t-butylperoxy)butyl chloroformate(86.3 percent) and 3.6 g. (0.05 mole) of ethylene glycol in 26 ml. ofacetone and 25 ml. of diethyl ether at 20:: 1 C. was added a solution of7.9 g. (0.1 mole) of pyridine in 10 ml. of diethyl ether. The mixturewas allowed to react for 24 hours at 25: 1 C. At the end of this periodthe reaction mixture was filtered off from the pyridine hydrochlorideand the organic phase washed with 100 ml. 10 percent solution oftartaric acid and water to neutrality. The ether solution was dried overanhydrous MgSO filtered and the solvent evaporated under reducedpressure.

A yield of 15.2 g. was obtained. The IR. of this material showed thecharacteristic bands of the desired compound with little contaminationof hydroxyl-containing material.

EXAMPLE IX Preparation of Di[1,3-dimethyl-3-(t-butylperoxy)butyl] ethylphosphate To a mixture of 22.1 g. (0.1 mole) of2-methyl-2-(tbutylperoxy)-4-pentanol (86 percent) and 7.9 g. (0.1 mole)of pyridine in 50 ml. of diethyl ether cooled at 5:: 1 C. was added asolution of 8.14 g. (0.05 mole) of ethyl dichlorophosphonate in ml. ofdiethyl ether.

After the addition was completed the reaction mixture was allowed tostir at 25: 1 C. for 24 hours.

At the end of this time the reaction mixture was filtered from thepyridine hydrochloride and it was washed with 10 percent solution oftartaric acid and water to neutrality. The ether solution was dried overanhydrous MgSO filtered and the solvent evaporated under reducedpressure. A liquid was obtained (13 g.). The IR. indicated that thedesired product was prepared. 1

EXAMPLE X Preparation of N,N'-m-phenylene bis[ l,3-dimethyl-3-(t-butyl-peroxy)butyl carbamate] A mixture of 4.2 g. (0.02 mole) of1,3-dimethyl-3-(tbutylperoxy)butanol (91 percent) and 1.6 g. (0.01 mole)of m-phenylenediisocyanate and few crystals of triethylene diamine and40 ml. of hexane was placed 12 into a dry flask, equipped with magneticstirrer, ther mometer, condenser and drying tube.

The mixture was allowed to stir for 4 hours at 50 to C. At the end ofthis time the reaction mixture contained an insoluble organic material.

This material was separated and the trace amount of solvent strippedunder reduced pressure. A viscous liquid weighing 1.8 g. was obtained.The LR. indicated that the desired product was obtained.

EXAMPLE XI Preparation of 2,2-bis[3,3-di(tbutylperoxy)butoxy]propane Amixture of 21.0 g. (0.08 mole) of 3,3-di(t-butylperoxy)butanol (96.6percent), 4.2 g. (0.04 mole) of 2,2-dimethoxypropane, 25 ml. of benzeneand 0.002 g. of p-toluensulfonic acid were combined and the mixture wasdistilled under atmospheric pressure. When 13 ml. of distillate boilingfrom 57 to 59 C. was collected, the distillation was stopped.

The pot residue was cooled down to 23 to 25 C. and neutralized withanhydrous Na CO The mixture was filtered and the remaining solventevaporated under reduced pressure. A liquid weighing 19.2 g. wasobtained. The IR. indicated that the desired product was prepared.

EXAMPLE Xll Preparation ofBis(2[1,3-dimetl'iyl-3-(t-butylperoxy)butoxy-carboxamido]ethyl) fumarate13 EXAMPLE xm CRQSSLINKABLE COIWPOS ITIONS A mixture of the desiredpolymeric material and 0.01 mole of the difunctional coupled compound isblended together on a standard roll mill, such as used in the rubberindustry. The mixture is removed from the roll mill and a portion isplaced in a press mold and heat cured at a determined temperature for aperiod of ee e The slabs are permitted to cool down and mature at roomtemperature for 24 hours. The mature slabs were then cut into dumbellshaped samples and tested for tensile strength on an lnstron TensileTester, following ASTM procedure as described in D412-61T TensionTesting of Vulcanized Rubber or the crosslinking in the case ofpolyethylene is determined by the solvent extraction procedure. Inaddition to the polymerperoxide mixture, the crosslinkable mixture, maycontain co-agents such as sulfur, promoters, fillers, and reinforcingmaterials. Desirable fillers are carbon black, titanium dioxide, calciumsilicate and alkaline earth metal carbonates.

In Table l the crosslinking ability of the coupled compounds of ourinvention in polyethylene are cornpared to a hydroxy-containing peroxideand to difunctional peroxides. Tables 11, III, and 1V show theversatility of the product of our invention in urethane rubber,ethylene-propylene rubber and silicone rubber.

Percent crosslinking 1 Molar Peroxide cquivs. 340 F. 375 F.

Di[1,34limethyl-3-(t-butylperoxy)butyl] 0. 010 80. 3 89. 7

carbonate (Examples I, II, and IIDi[1,3-dimethyl-3-(t-butylperoxylbutyl] succinate (Example VII). 0.01088. 89. 2 Ethylene bisll,3-dimethyl-3-(t-butylperoxylbutyl carbonate]Example VIII). 0.010 87.0 87.4 2-methyl-2-( t-butylperoxyH-pcntanoL. 0.015 78. 4 75. 4 2,5-dimethyl-2 .5di(t-butylperoxy)- hexane. 0.010 85.084.5 2,5-dimethyl-2,5di(t-butylperoxy) I hexyne-3 0.010 81.8 84.02.5-dimethyl-2,5-di t butylperoxylhexane. 0.015 89.3 88.0 2,5-dinu-th.1-2.5-dl(t-butylperoxy)- hexyne-3 0.015 86.0 87.7

1 The percentage nrosslinking was determined by extraction of thecrosslinked sample with refluxing xylene. In all cases the polyethylenecharge was 100% extractable before crosslinking.

-' Based on number ol active oxygens per mole.

Nora--The polyethylene used for this test was a low density polyethylenecalled Bakelite DYNHA, having the following physical properties. Meltindex (ASTM Test l)1238)=190 C. 2.0 gJlO min.: Density ASTM Testl')1505) =0.010.

From the table it is obvious that the coupled compounds of our inventionare more eflicient than the hydroxy containing peroxide that they werederived from. This test also shows that the coupled compounds aresignificantl more efiicient at equal molar equivalents than otherdifunctional peroxides that are commercially used In crosslinkpolyethylene.

TABLE IL-VULCANIZATION 0F URE'IHANE RUBBER F0 RMULATION (.venthane-S,parts H.A.F. carbon black, 25 parts Stearic acid, 0.2 part 300% UltimatePercent Peroxide modulus tensile elongation Dill,3-dirnethyl-3-(t-butylperoxy)- butyllearbonate (Examples 1,

II, and III), p.s.i 2,001 4, 512 493 mu, 3-din1ethyl-3-(t-butylperoxy)-butyl]suecinate (Example VII),

p.s.i 1, -172 4, 167 575 Ethylene bis[1,3-dimethyl-3-(tbutylperoxy)butyl carbonate] (Example VIII) p.s.i 2, 410 3, 502 375 .Genthane-S is adesignation given to one of the polyurethane elastomers developed by TheGeneral Tire & Rubber Company, having the following properties: Mooneyviscosity (MLl 212 F.), 50110: specific gravity, 1.10.

1 H.A.F. carbon black is a high abrasion furnace black.

NorI-:.The cure was carried out with 0.010 mole equivalent of peroxideat 340 F. for 30 minutes. The urethane rubber charge without peroxidehas 0 to 100 p.s.i. 300% modulus.

TABLE lIL-VULCANIZATION OF ETHYLENE-PROPYL- ENE RUBBER FORMULATIONERR-404, 100 parts S.R.F. carbon black; 60 parts Sulfur, 0.33 partPeroxide, 0.010 mole equivalent Cure time, 30 minutes Cure temperature,340 F.

1 E.P.R.404 is an ethylene-propylene copolymer clastomeric materialmanufactured by Enjay, having specific gravity gJcc. 0.86. Mooneyviscosity at 212 F. (8 minutes) 40.

2 S. RF. carbon black is a semi-reinforcing furnace carbon blackmanufactored by Cabot Corporation.

N0'rE.-Without peroxide ethylene-propylene rubber copolymer has a 300%modulus of 0 to 100 p.s.i.

Modulus Tensile Elong. Di[ 1 ,3-dimethyl-3-(t-butylperoxy)butyl]carbonate (Examples 1, ll, & H1) 43 1 l Silicone Rubber-404 is a generalpurpose reinforced silicone gum manufactured by General Electric. Thesilicone rubber charge without peroxide has a 300 percent modulus of 0psi.

EXAMPLE XIV This example illustrates the use of coupled peroxides ofpresent disclosures as initiators of vinyl monomer polymerization.Compound [B] (from Example V) at a concentration of 5 X 10" moles perdeciliter of styrene, polymerized styrene at 100 C. at a rate of 6.20 X10 moles per liter per minute. When no initiator is present, As can beseen from the half-life values, the peroxthe thermal polymerization ofstyrene at 100 C. ides containing hydroxyl have significantly lowerhalfproceeds at a rate of 2.82 X 10' moles per liter per lives than thecoupled compounds. Thus, the coupled minute. Compound [A] (from Examples1, II, and III) peroxides are more thermally stable and safer to hanat aconcentration of X moles per diciliter of 5 dle, ship, store and use.styrene polymerized styrene 1.65 faster at 1 C. than Thus havingdescribed the invention, what is claimed the thermal polymerization ratewhen no polymerizaiSI tion initiator is present. 1. A peroxide of theformula R-W-R where:

EXAMPLE Xv m a. W is a drradrcal) selected) from O Curing An UnsaturatedPolyester-Styrene Resin With and Coupled Peroxide An unsaturatedpolyester resin was made by reacting R and are identical and areSelected from maleic anhydride (1.0 mole), phthalic anhydride (1.0

mole), and propylene glycol (2.2 mole) until an acid 15 I It O0CR O-, R-0o- C--R O number of 45-50 was obtained. To this was added a 3 )1hydroquinone at a 0.013 percent concentration. Seven parts of thisunsaturated polyester was diluted with 3 H if parts of monomeric styreneto obtain a homogeneous RPOCFCFRFCF- *Q blend having a viscosity of13.08 poise and a specific gravity of 1.14. To 20 g. of this blend wasadded the 0.2 R1-0C0 0(I3-R O and R100 0(lJ-R O- g. of the desiredcoupled peroxide and the resulting R, R, composition placed in aconstant temperature bath at 1 15 C. c. R and R are C hydrocarbonaliphatic;

The internal temperature was recorded as function d. R, is C hydrocarbonaliphatic and the carbon of time. The following results were obtainedwith some atom joined to the peroxy oxygen atom is a tertiary of thecoupled compounds (Table V): carbon;

TABLE V.S.l.l. EXO'IIIERM AT 115 C. AND 1% CONCENTRATION IN POLYESTERRESIN PREPARED IN EXAMPLE VIII NOTE. Without an initiator, no cure ofthis resin blend occurred after more than minutes at 1 15 C.

e. R, is C hydrocarbon aliphatic;

EXAMPLE XVI 40 f. R, is H or lower alkyl; g. Y is the diradical -O-;Half-Life Comparisons of coupled and Uncoupled h R i c h d b li h i didi l; Hydroxy-Peroxides (Carried out in Benzene at 0.1 i, R i a (j h d bli h i or C molar concentrations) hydrocarbon aromatic diradical; and j.R is a diradical selected from -YR Y-,

' t, 1 o 0 0 li-roxulv hour 0. YR Y(HJR (HJYR Y YR YgR Y (I In (I m 13.6 115 and YR3YR3Y HPSFCHPCIFOH 2. Claim 1 wherein said peroxide isdi[2-(t-butyl- 8 II peroxy-carbonyl)-ethyl] carbonate. (1 M 3. Claim 1wherein said peroxide is di[ 1 ,3-dimethyl-32-1nvthyl-2-(t4iutylpvr0xy)-4punLzuml (n-butCDWCarbOI-lflperox),)butyl]carbonate 4. A process for preparing coupled peroxy compounds of claim1, which process comprises:

a. reacting, at a temperature of from 10 C. to not t) ll more than 100C., about two moles of a hydroxycontaining peroxide with about one moleof a hydroxy coupling agent selected from phosgene l i| l .zs-rlinwill14 t-lmi uwm 1 and bischloroformates and hutyll t'illhmlitlu (ExumplvsI, ll, & Ill) b recovering the couplgd peroxy compound from the reactionmixture. u1[ho o(i a -(21124:na -on 5. A process for preparing coupledperoxy com- (111;, pounds of claim 1 by the interaction of ahydroxy-cont-liutylpcroxy 3-liydroxypr0pionatc taming peroxide with ahydroxy coupling agent Cm O 0 am 100 selected from phosgene andbischloroformates, which H process comprises: 7' a. reacting one molarequivalent of said hydroxyon; 2 containing peroxide with said hydroxycoupling m{2 (t buty1mmxycarbonyncmyn agent at a temperature of fromabout -10 to +25 carbonate (Example V) C. to form an intermediate peroxycompound;

b. reacting said intermediate compound at a temperature of not more than100 C. in an amount sufficient to couple with a compound selected fromthe class consisting of dihydroxy compounds and said hydroxy-containingperoxide to form a coupled peroxy compound; and

c. recovering the coupled peroxy compound from the reaction mixture.

6. Di[ 1 ,3-dimethyl-3-(t-butylperoxy )butyl] bonate.

7. Di[4,4-di(t-butylperoxy)pentyl] carbonate.

8. Ethylene Bis[ l,3-dimethyl-3-(t-butylperoxy)- butyl carbonate].

9. A process for the preparation of di( 1,3-dimethyl- 3-(t-butylperoxy)butyl) carbonate which process comprises:

a. intermixing, at a temperature of about C. in the presence of a base,one molar equivalent of phosgene and two molar equivalents of 2-methyl-2-(t-butylperoxy)4-pentanol;

b. increasing the reaction temperature gradually to not more than about50 C., for a time sufficient to complete the reaction; and

c. recovering the wanted product from the reaction car- mixture. l0. Aprocess for the preparation of ethylene bis[ 1,3-dimethyl-3-(t-butylperoxy )butyl carbonate] which process comprises:

a. reacting at a temperature of about 5 C. equimolar amounts of phosgeneand 2-methyl-2-(t-butylperoxy )-4-penta.nol, to form1,3-dirnethyl-3-(t-butylperoxy )butyl chloroformate;

b. reacting, at a temperature of about 20 to 25 C. and in the presenceof a base two molar equivalents of said peroxy containing chloroformateand one molar equivalent of ethylene glycol, for a time sufficient tocomplete the reaction; and

c. recovering the product from the reaction mixture.

1 1. A process for the preparation of a coupled peroxy containingcompound which process comprises:

a. reacting one molar equivalent of hydroxy-containing peroxy compoundwith phosgene at a temperature of from about l0 to +25 C. to form anintermediate peroxy containing chloroformate com- P b. admixingequimolar amounts of said peroxy con taining chlo'roformate compound anda tertiaryamine;

c. adding water at a rate and temperature sufficient to control theevolution of carbon dioxide;

d. continuing the reaction until the evolution of carbon dioxide ceases;and

e. recovering the product from the reaction mixture.

12. A process for the preparation of di[ 1,3-dimethyl-3-(t-butylperoxy)butyl] carbonate which process comprises:

a. reacting at a temperature of about 5 C. equimolar amounts of phosgeneand 2-methyl-2-(t-butylperoxy)4-pentanol, to forml,3-dimethyl-3-(t-butylperoxy)butyl chloroformate;

b. admixing equimolar amounts of said peroxy chloroformate and pyridineat about 23 C.;

c. adding water at a rate sufficient to control the evolution of carbondioxide;

d. continuing the reaction at about 23 C. until the evolution of carbondioxide ceases; and

e. recovering the product from the reaction mixture.

2. Claim 1 wherein said peroxide is di(2-(t-butylperoxy-carbonyl)-ethyl)carbonate.
 3. Claim 1 wherein said peroxide isdi(1,3-dimethyl-3-(n-butoxycarbonylperoxy)butyl) carbonate.
 4. A processfor preparing coupled peroxy compounds of claim 1, which processcomprises: a. reacting, at a temperature of from -10* C. to not morethan 100* C., about two moles of a hydroxy-containing peroxide withabout one mole of a hydroxy coupling agent selected from phosgene andbischloroformates, and b. recovering the coupled peroxy compound fromthe reaction mixture.
 5. A process for preparing coupled peroxycompounds of claim 1 by the interaction of a hydroxy-containing peroxidewith a hydroxy coupling agent selected from phosgene andbischloroformates, which process comprises: a. reacting one molarequivalent of said hydroxy-containing peroxide with said hydroxycoupling agent at a temperature of from about -10* to +25* C. to form anintermediate peroxy compound; b. reacting said intermediate compound ata temperature of not more than 100* C. in an amount sufficient to couplewith a compound selected from the class consisting of dihydroxycompounds and said hydroxy-containing peroxide to form a coupled peroxycompound; and c. recovering the coupled peroxy compound from thereaction mixture.
 6. Di(1,3-dimethyl-3-(t-butylperoxy)butyl) carbonate.7. Di(4,4-di(t-butylperoxy)pentyl) carbonate.
 8. EthyleneBis(1,3-dimethyl-3-(t-butylperoxy)-butyl carbonate).
 9. A process forthe preparation of di(1,3-dimethyl-3-(t-butylperoxy)butyl) carbonatewhich process comprises: a. intermixing, at a temperature of about 5* C.in the presence of a base, one molar equivalent of phosgene and twomolar equivalents of 2-methyl-2-(t-butylperoxy)-4-pentanol; b.increasing the reaction temperature gradually to not more than about 50*C., for a time sufficient to complete the reaction; and c. recoveringthe wanted product from the reaction mixture.
 10. A process for thepreparation of ethylene bis(1,3-dimethyl-3-(t-butylperoxy)butylcarbonate) which process comprises: a. reacting at a temperature ofabout 5* C. equimolar amounts of phosgene and2-methyl-2-(t-butylperoxy)-4-pentanol, to form 1,3-dimethyl-3-(t-butylperoxy)butyl chloroformate; b. reacting, at atemperature of about 20* to 25* C. and in the presence of a base twomolar equivalents of said peroxy containing chloroformate and one molarequivalent of ethylene glycol, for a time sufficient to complete thereaction; and c. recovering the product from the reaction mixture.
 11. Aprocess for the preparation of a coupled peroxy containing compoundwhich process comprises: a. reacting one molar equivalent ofhydroxy-containing peroxy compound with phosgene at a temperature offrom about -10* to +25* C. to form an intermediate peroxy containingchloroformate compound; b. admixing equimolar amounts of said peroxycontaining chloroformate compound and a tertiary-amine; c. adding waterat a rate and temperature sufficient to control the evolution of carbondioxide; d. continuing the reaction until the evolution of carbondioxide ceases; and e. recovering the product from the rEaction mixture.12. A process for the preparation ofdi(1,3-dimethyl-3-(t-butylperoxy)butyl) carbonate which processcomprises: a. reacting at a temperature of about 5* C. equimolar amountsof phosgene and 2-methyl-2-(t-butylperoxy)-4-pentanol, to form 1,3-dimethyl-3-(t-butylperoxy)butyl chloroformate; b. admixing equimolaramounts of said peroxy chloroformate and pyridine at about 23* C.; c.adding water at a rate sufficient to control the evolution of carbondioxide; d. continuing the reaction at about 23* C. until the evolutionof carbon dioxide ceases; and e. recovering the product from thereaction mixture.